La Jolla scientists train eyes on gray giants

Federal biologists count whales migrating past Carmel from trailers such as this one. Besides big binoculars, they have thermal imaging devices to help them track whales that are underwater or pass during the night.
— National Marine Fisheries Service

Federal biologists count whales migrating past Carmel from trailers such as this one. Besides big binoculars, they have thermal imaging devices to help them track whales that are underwater or pass during the night.
/ National Marine Fisheries Service

Perched in trailers on a seaside cliff near Carmel, David Weller and his fellow researchers from La Jolla will spend two more weeks counting gray whales as they splash south to the subtropical lagoons of Baja California for mating and birthing.

The annual swim meet typically holds few big surprises, but biologists from the local office of the National Marine Fisheries Service spend their winters watching one of the longest migrations on Earth and looking for signs that the giant creatures might be in trouble.

The fisheries service’s data about the southern migration of gray whales near Carmel goes back to 1967, providing scientists with an valuable record of a species that once was decimated by whaling but now is considered abundant. Over the past four decades, its numbers have climbed from about 13,500 to roughly 20,000 -- a few of which have become locally famous by turning into San Diego Bay on their migrations.

The revival means gray whales are no longer considered an endangered species, though scientists aren’t sure what effects climate change will have on their feeding habitat in the Arctic. Today, the whales may be approaching the capacity of the coastal environment to support them.

It’s a different story elsewhere. Gray whales are extinct in the North Atlantic and they are nearly so in the western Pacific, where whaling is blamed for their demise. One recent assessment suggests there are only about 130 gray whales in that region because of whaling off the coast of Asia.

Besides tracking the overall count of the population off the California coast, Weller and his colleagues track the timing of the migration — which has shifted slightly later over the years — and the number of calves that are born before they reach Carmel.

About two days after southbound whales are spotted at the Granite Canyon research outpost, they pass San Diego on their way to their winter calving grounds.

Then, they turn around and head back north past San Diego on another 5,000-mile journey for summer feeding off Alaska. Researchers from the fisheries service also set up shop at Piedras Blancas Light Station near San Simeon to count cow-calf pairs migrating north from March through May.

It’s not just researchers who are intrigued by the whales. Each year, an estimated 2 million people from San Diego to Seattle board guided tours in hopes of catching an up-close glimpse of the passing giants.

“The sightings have been fantastic,” said Janet Morris at the San Diego Natural History Museum, which provides naturalists to narrate tours run by Hornblower Cruises. “They saw 12 whales on (a recent trip), including some breeding behavior. That’s a rare sight. Many cow-calf pairs (and) tons of dolphins.”

Weller doesn’t need a tour boat to see hundreds of whales a day at the peak of migration, when more than a dozen pods may be passing his overlook at any one time. The underwater terrain just south of Monterey Bay tends to keep the whales within a mile or two of the shore at Granite Canyon.